Subversion Repositories neorv32

-- #################################################################################################

-- # << NEORV32 - System/Processor Configuration Information Memory (SYSINFO) >>                   #

-- # ********************************************************************************************* #

-- # This unit provides information regarding the 'system' configuration - mostly derived from the #

-- # top's configuration generics.                                                                 #

-- # ********************************************************************************************* #

-- # BSD 3-Clause License                                                                          #

-- #                                                                                               #

-- # Copyright (c) 2020, Stephan Nolting. All rights reserved.                                     #

-- #                                                                                               #

-- # Redistribution and use in source and binary forms, with or without modification, are          #

-- # permitted provided that the following conditions are met:                                     #

-- #                                                                                               #

-- # 1. Redistributions of source code must retain the above copyright notice, this list of        #

-- #    conditions and the following disclaimer.                                                   #

-- #                                                                                               #

-- # 2. Redistributions in binary form must reproduce the above copyright notice, this list of     #

-- #    conditions and the following disclaimer in the documentation and/or other materials        #

-- #    provided with the distribution.                                                            #

-- #                                                                                               #

-- # 3. Neither the name of the copyright holder nor the names of its contributors may be used to  #

-- #    endorse or promote products derived from this software without specific prior written      #

-- #    permission.                                                                                #

-- #                                                                                               #

-- # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS   #

-- # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF               #

-- # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE    #

-- # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,     #

-- # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE #

-- # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED    #

-- # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING     #

-- # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED  #

-- # OF THE POSSIBILITY OF SUCH DAMAGE.                                                            #

-- # ********************************************************************************************* #

-- # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #

-- #################################################################################################

library ieee;

use ieee.std_logic_1164.all;

use ieee.numeric_std.all;

library neorv32;

use neorv32.neorv32_package.all;

entity neorv32_sysinfo is

  generic (

    -- General --

    CLOCK_FREQUENCY   : natural := 0;      -- clock frequency of clk_i in Hz

    BOOTLOADER_USE    : boolean := true;   -- implement processor-internal bootloader?

    USER_CODE         : std_ulogic_vector(31 downto 0) := x"00000000"; -- custom user code

    -- Memory configuration: Instruction memory --

    MEM_ISPACE_BASE   : std_ulogic_vector(31 downto 0) := x"00000000"; -- base address of instruction memory space

    MEM_ISPACE_SIZE   : natural := 8*1024; -- total size of instruction memory space in byte

    MEM_INT_IMEM_USE  : boolean := true;   -- implement processor-internal instruction memory

    MEM_INT_IMEM_SIZE : natural := 8*1024; -- size of processor-internal instruction memory in bytes

    MEM_INT_IMEM_ROM  : boolean := false;  -- implement processor-internal instruction memory as ROM

    -- Memory configuration: Data memory --

    MEM_DSPACE_BASE   : std_ulogic_vector(31 downto 0) := x"80000000"; -- base address of data memory space

    MEM_DSPACE_SIZE   : natural := 4*1024; -- total size of data memory space in byte

    MEM_INT_DMEM_USE  : boolean := true;   -- implement processor-internal data memory

    MEM_INT_DMEM_SIZE : natural := 4*1024; -- size of processor-internal data memory in bytes

    -- Memory configuration: External memory interface --

    MEM_EXT_USE       : boolean := false;  -- implement external memory bus interface?

    -- Processor peripherals --

    IO_GPIO_USE       : boolean := true;   -- implement general purpose input/output port unit (GPIO)?

    IO_MTIME_USE      : boolean := true;   -- implement machine system timer (MTIME)?

    IO_UART_USE       : boolean := true;   -- implement universal asynchronous receiver/transmitter (UART)?

    IO_SPI_USE        : boolean := true;   -- implement serial peripheral interface (SPI)?

    IO_TWI_USE        : boolean := true;   -- implement two-wire interface (TWI)?

    IO_PWM_USE        : boolean := true;   -- implement pulse-width modulation unit (PWM)?

    IO_WDT_USE        : boolean := true;   -- implement watch dog timer (WDT)?

    IO_TRNG_USE       : boolean := true;   -- implement true random number generator (TRNG)?

    IO_DEVNULL_USE    : boolean := true    -- implement dummy device (DEVNULL)?

  );

  port (

    -- host access --

    clk_i  : in  std_ulogic; -- global clock line

    addr_i : in  std_ulogic_vector(31 downto 0); -- address

    rden_i : in  std_ulogic; -- read enable

    data_o : out std_ulogic_vector(31 downto 0); -- data out

    ack_o  : out std_ulogic  -- transfer acknowledge

  );

end neorv32_sysinfo;

architecture neorv32_sysinfo_rtl of neorv32_sysinfo is

  -- IO space: module base address --

  constant hi_abb_c : natural := index_size_f(io_size_c)-1; -- high address boundary bit

  constant lo_abb_c : natural := index_size_f(sysinfo_size_c); -- low address boundary bit

  -- access control --

  signal acc_en    : std_ulogic; -- module access enable

  signal addr      : std_ulogic_vector(31 downto 0);

  signal rden      : std_ulogic;

  signal info_addr : std_ulogic_vector(02 downto 0);

  -- system information ROM --

  type info_mem_t is array (0 to 7) of std_ulogic_vector(31 downto 0);

  signal sysinfo_mem : info_mem_t;

begin

  -- Access Control -------------------------------------------------------------------------

  -- -------------------------------------------------------------------------------------------

  acc_en    <= '1' when (addr_i(hi_abb_c downto lo_abb_c) = sysinfo_base_c(hi_abb_c downto lo_abb_c)) else '0';

  rden      <= acc_en and rden_i; -- valid read access

  addr      <= sysinfo_base_c(31 downto lo_abb_c) & addr_i(lo_abb_c-1 downto 2) & "00"; -- word aligned

  info_addr <= addr(index_size_f(sysinfo_size_c)-1 downto 2);

  -- Construct Info ROM ---------------------------------------------------------------------

  -- -------------------------------------------------------------------------------------------

  -- SYSINFO(0): Processor (primary) clock frequency --

  sysinfo_mem(0) <= std_ulogic_vector(to_unsigned(CLOCK_FREQUENCY, 32));

  -- SYSINFO(1): Custom user code --

  sysinfo_mem(1) <= USER_CODE;

  -- SYSINFO(2): Implemented processor devices/features --

  -- Memory

  sysinfo_mem(2)(00) <= bool_to_ulogic_f(BOOTLOADER_USE);   -- implement processor-internal bootloader?

  sysinfo_mem(2)(01) <= bool_to_ulogic_f(MEM_EXT_USE);      -- implement external memory bus interface?

  sysinfo_mem(2)(02) <= bool_to_ulogic_f(MEM_INT_IMEM_USE); -- implement processor-internal instruction memory?

  sysinfo_mem(2)(03) <= bool_to_ulogic_f(MEM_INT_IMEM_ROM); -- implement processor-internal instruction memory as ROM?

  sysinfo_mem(2)(04) <= bool_to_ulogic_f(MEM_INT_DMEM_USE); -- implement processor-internal data memory?

  sysinfo_mem(2)(15 downto 05) <= (others => '0'); -- reserved

  -- IO

  sysinfo_mem(2)(16) <= bool_to_ulogic_f(IO_GPIO_USE);      -- implement general purpose input/output port unit (GPIO)?

  sysinfo_mem(2)(17) <= bool_to_ulogic_f(IO_MTIME_USE);     -- implement machine system timer (MTIME)?

  sysinfo_mem(2)(18) <= bool_to_ulogic_f(IO_UART_USE);      -- implement universal asynchronous receiver/transmitter (UART)?

  sysinfo_mem(2)(19) <= bool_to_ulogic_f(IO_SPI_USE);       -- implement serial peripheral interface (SPI)?

  sysinfo_mem(2)(20) <= bool_to_ulogic_f(IO_TWI_USE);       -- implement two-wire interface (TWI)?

  sysinfo_mem(2)(21) <= bool_to_ulogic_f(IO_PWM_USE);       -- implement pulse-width modulation unit (PWM)?

  sysinfo_mem(2)(22) <= bool_to_ulogic_f(IO_WDT_USE);       -- implement watch dog timer (WDT)?

  sysinfo_mem(2)(23) <= '0';

  sysinfo_mem(2)(24) <= bool_to_ulogic_f(IO_TRNG_USE);      -- implement true random number generator (TRNG)?

  sysinfo_mem(2)(25) <= bool_to_ulogic_f(IO_DEVNULL_USE);   -- implement dummy device (DEVNULL)?

  sysinfo_mem(2)(31 downto 26) <= (others => '0'); -- reserved

  -- SYSINFO(3): reserved --

  sysinfo_mem(3) <= (others => '0'); -- reserved - maybe for technology-specific configuration options?

  -- SYSINFO(4): Base address of instruction memory space --

  sysinfo_mem(4) <= MEM_ISPACE_BASE;

  -- SYSINFO(5): Base address of data memory space --

  sysinfo_mem(5) <= MEM_DSPACE_BASE;

  -- SYSINFO(6): Total size of instruction memory space in bytes --

  sysinfo_mem(6) <= std_ulogic_vector(to_unsigned(MEM_ISPACE_SIZE, 32));

  -- SYSINFO(7): Total size of data memory space in bytes --

  sysinfo_mem(7) <= std_ulogic_vector(to_unsigned(MEM_DSPACE_SIZE, 32));

  -- Read Access ----------------------------------------------------------------------------

  -- -------------------------------------------------------------------------------------------

  read_access: process(clk_i)

  begin

    if rising_edge(clk_i) then

      ack_o <= rden;

      if (rden = '1') then

        data_o <= sysinfo_mem(to_integer(unsigned(info_addr)));

      else

        data_o <= (others => '0');

      end if;

    end if;

  end process read_access;

end neorv32_sysinfo_rtl;